Management method and a management system for volume

ABSTRACT

It is made possible to update information registered in a database of iSNS, SLP and the like in response to a configurational change in a storage device, and for a host computer to discover a disk volume. In response to changes in contents of operation to alter a storage configuration such as in creating or deleting a volume or LUN, contents of the alteration are reflected in the database of iSNS or SLP. Also, in response to a change in setting of LUN masking, a discovery domain of iSNS or attribute values of SLP are updated so that the host computer can discover the disk volume. Also, objects and services are reregistered periodically according to a registration period of iSNS or lifetime of SLP to prevent registered contents from expiring.

CROSS-REFERENCE TO RELATED APPLICATION

The present application is a continuation application Ser. No.13/186,904, filed Jul. 20, 2011; which is a continuation of applicationSer. No. 12/564,162, filed Sep. 22, 2009, now U.S. Pat. No. 8,006,063,which is a continuation application of Ser. No. 11/905,889, filed Oct.5, 2007, now U.S. Pat. No. 7,610,467, which is a continuationapplication of application Ser. No. 11/290,123, filed Nov. 29, 2005, nowU.S. Pat. No. 7,296,131, which is a continuation application ofapplication Ser. No. 10/894,983, filed Jul. 19, 2004, now U.S. Pat. No.7,010,660, which claims priority from Japanese application JP2004-150225, filed on May 20, 2004, the contents of which are herebyincorporated by reference into this application.

BACKGROUND OF THE INVENTION

The following description relates to a management method and managementsystem for storage areas, and more particularly to a management methodfor storage areas applicable in storage devices, accessed by use of theInternet SCSI (iSCSI) Protocol, to name servers and directories when theconfiguration of storage areas has been altered and to a managementsystem for executing it.

Storage Area Network (SAN) environments in which host computers andstorage devices, such as disk arrays, are connected by a network are ingrowing use. More recently, interest is focused on the Internet SCSI(iSCSI) which uses an IP network as the SAN and communicates data bymounting the SCSI Protocol on the Transmission Control Protocol (TCP).The iSCSI has the advantage of allowing low-cost architecture of a SANby making use of existing IP switches and ether cables. An entity forperforming iSCSI Protocol communication has “storage nodes” and“portals”. A storage node has a unique identifier “iSCSI name” andbecomes the sender and receiver of communication. A portal has a networkaddress and provides means of communication. A storage node sends andreceives data by mutual communication via a portal.

Details of the iSCSI are described in the following reference, JulianSatran et al., Internet Draft, draft-ietf-ips-iscsi-20.txt, pp. 20-48.

An IP network makes possible communication with geographically distantsites, and the number of devices that can be connected within a singlenetwork is far greater than what a fiber channel or the like canaccommodate. For this reason, if information regarding storage areasaccessible by host computers (for instance disk volumes created on adisk array as logical areas) are individually set for each hostcomputer, their management will entail complex work. In view of thisproblem, there is proposed a method by which disk volumes can bediscovered without having to set information on disk volumes for eachhost computer by placing many nodes that communicate by the iSCSIProtocol under centralized management in a database and having each hostcomputer to acquire information it needs from the database.

Regarding this method, for instance the reference, Josh Tseng et al.,Internet Draft, draft-ietf-ips-isns-22.txt, pp. 7-13 describes theInternet Storage Name Service (iSNS) in which information on devicescapable to be communicated by the iSCSI Protocol is centrally managed.Thus, by having the addresses and port numbers of portals used by agiven storage node for communication registered in the iSNS, otherstorage nodes are enabled to discover that node and to acquire from theiSNS the address they need for communication. Further by dividing eachstorage node to be managed into groups called discovery domains, thenodes which a given storage node can discover can be limited to nodesregistered in the same domain.

Further, the following reference, Mark Bakke et al., Internet Draft,draft-ietf-ips-iscsi-slp-07.txt, pp. 4-14, describes a method by whichiSCSI nodes are discovered by use of a Service Location Protocol (SLP)which manages information on the services provided within the network.Thus, by registering one storage node and the address and port number ofone portal which the node uses for communication in the SLP DirectoryAgent as the URL of the service, discovery from other nodes is madepossible. Further, by designating the node which is permitted tocommunicate as an attribute of a service to be registered, each node candiscover only those nodes it can communicate with.

SUMMARY OF THE INVENTION

In an environment in which the discovery of a storage node in iSCSI usesa database of iSNS or SLP, when the configuration of the storage devicehas been altered by the creation or deletion of a disk volume or alogical unit number (LUN), a difference arises between the registeredcontents in the database and the actual configuration of the storagedevice. This would lead to a situation in which normal discovery isprevented by the difference between the actual configuration and theregistered contents in the database.

Or where a storage device has for each LUN a list of the iSCSI names ofhost computers and a LUN masking function, which allows only the hostcomputers recorded in the list to access any LUN, is provided, in orderto allocate LUNs to a given host computer, LUN masking is set bydesignating the iSCSI name of that host computer. However, in anenvironment in which a host computer discovers a target device by use ofiSNS, if the host computer and the disk volume belong to differentdiscovery domains, even if LUN masking is set, the host computer cannotdiscover the allocated disk volume, and accordingly the volumeallocation intended by the manager cannot be realized. Similarly, in anenvironment using SLP, unless host computers which can access theattribute of the disk volume registered as a service under SLP are notregistered, none of the host computers can discover any accessible diskvolume.

Thus, neither iSNS nor SLP according to the prior art has a mechanism todetect any change in storage device configuration and cause it to bereflected in the contents registered in the database. For this reason,when the storage configuration has been altered, no normal discovery ispossible until the manager manually updates the database. Moreover,manual updating of the database involves the risk of oversight inregistration, wrong registration or unintended deletion of registereditems. No manual operation can practically meet the need to alter manydisk volumes promptly, and this would invite an unmanageable situation.

As a mode for implementation to solve the problems noted above, contentsof any alteration in storage device configuration are caused to bereflected in an information service device via a network. When a volumewhose area is logically defined has been created in a storage device,information including at least the iSCSI name of the created volume iscaused to be reflected in the information service device via thenetwork. Or when a LUN has been created in a storage device, informationincluding the matching relationship between the volume and the port ofthe created LUN is caused to be reflected in the information servicedevice via the network. Further, when a volume has been deleted from astorage device, processing to delete the registration of the storagenode matching that volume from the information service device isperformed. Or when LUN masking is set for a given volume and allocatedto a host computer, in an environment in which the iSNS Protocol is tobe used, the domain configuration is so altered that the allocatedvolume and the host computer belong to the same discovery domain.

Or in an environment in which the SLP is used, the iSCSI name of thehost computer is registered as an attribute of service representing theallocated volume.

Preferably, the mode should be realized by a management method forstorage areas or system to perform processing to provide information onstorage devices to be registered to an information service device inwhich are registered to be managed information on devices capable ofcommunication by a specific protocol, for instance the iSCSI Protocol.

Each storage device holds storage areas each having a unique identifier,network interfaces each having a network address uniquely allocated in anetwork, and a matching relationship between storage areas and networkinterfaces, and executes the transmission or updating of the matchingrelationship in response to a request received via the network.

A management server managing the configuration of the storage devicesacquires, from each storage device, the network address of the networkinterface and the matching relationship between storage areas andnetwork interfaces and, further for registration in a database which theinformation service device has, transmits to the information servicedevice a request for registration of the matching relationship betweenstorage areas and network interfaces including the identifier of eachstorage area and the network address of the matching network interface.

In a preferable case, the storage areas should be logically definedvolumes formed in the pertinent storage device, the storage device isaccessed by the host computer using the iSCSI Protocol, and theinformation service device is a management database or an iSNS server,communication between the information service device and the managementserver being accomplished by the iSNS Protocol.

The management server, in a preferable case, should comprise a memorystoring a storage device table for recording at least the IP address andthe TCP port number of each storage device to be managed and anidentifier to the iSCSI device in the network; an iSNS address table forrecording the IP address of the iSNS server; a management program formanaging the storage device; and a CPU for executing the managementprogram.

Preferably, this CPU should perform first processing, when theconfiguration of the pertinent storage device has been altered, to sendinformation on that alteration to the iSNS server via the network tohave it reflected in the database; second processing, when a logicallydefined volume has been created in the pertinent storage device, to sendinformation including at least the iSCSI name of the created volume tothe information service device via the network to have it reflected inthe database; and third processing, when a LUN has been created in thepertinent storage device, to send information including the matchingrelationship between the volume and the port of the created LUN to theiSNS server via the network to have it reflected in the database.

In another preferable case, in a system in which storage devices havingan iSNS client function and storage devices having no iSNS clientfunction are in mixed presence, each of the storage devices should holda storage area having a unique identifier, a network interface having anetwork address uniquely allocated in a network, a matching relationshipbetween the storage area and the network interface, and information onwhether or not the storage device has an iSNS client function, thedevice having a step of executing, in response to a request received viathe network, transmission or updating of the matching relationship, themanagement server having a step of causing communication of informationon the configuration of storage devices to take place between storagedevices having an iSNS client function and storage devices having noiSNS client function; a step of acquiring from any storage device thenetwork address of the network interface, the matching relationshipbetween the storage area and the network interface; a step of acquiringinformation on whether or not the storage device has an iSNS clientfunction; a step of assessing the acquired information on the presenceor absence of an iSNS client function; a step of registering, on thebasis of the assessment, the address of the iSNS server in the storagedevice having an iSNS client function; an edit processing step ofediting, on the basis of the assessment, the name of the storage area ofthe storage device and the port name for the network interface for thestorage device having no iSNS client function; and a step oftransmitting to the information service device a request for registeringthe identifier of the storage area, the identifier of the storage areaincluding the network address of the matching the network interface, andthe matching relationship of the address of the network interface.

Other features of these methods and systems will become apparent fromthe following description in this specification when taken inconjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows the overall configuration of a system to which Embodiment 1is applied.

FIG. 2 shows the configuration of a storage device table 2025 inEmbodiment 1.

FIG. 3 shows the configuration of a port table 4055 in Embodiment 1.

FIG. 4 shows the configuration of a volume table 4060 in Embodiment 1.

FIG. 5 shows the configuration of an entity table 1025 in Embodiment 1.

FIG. 6 shows the configuration of a storage node table 1030 inEmbodiment 1.

FIG. 7 shows the configuration of a portal table 1035 in Embodiment 1.

FIG. 8 shows the configuration of a portal group table 1040 inEmbodiment 1.

FIG. 9 shows the configuration of a discovery domain table 1045 inEmbodiment 1.

FIG. 10 is a flowchart of initial registration processing in Embodiment1.

FIG. 11 shows the configuration of a message of registering a portal inEmbodiment 1.

FIG. 12 shows the configuration of a message of registering a storagenode and a portal group in Embodiment 1.

FIG. 13 is a flowchart of the operation of a disk array controllerprogram for disk arrays in Embodiment 1.

FIG. 14 shows the configuration of a message of registering a volume inEmbodiment 1.

FIG. 15 shows the configuration of a message of deleting a volume inEmbodiment 1.

FIG. 16 is a flowchart of the operation of a management program 2020 inEmbodiment 1.

FIG. 17 shows the configuration of a message of registering the creationand deletion of a LUN in Embodiment 1.

FIG. 18 is a flowchart of processing the additional setting of LUNmasking in Embodiment 1.

FIG. 19 shows the configuration of a message of acquiring a list ofdiscovery domains in Embodiment 1.

FIG. 20 shows the configuration of a message of acquiring a list ofmembers in a discovery domain in Embodiment 1.

FIG. 21 shows the configuration of a message of acquiring the node typeand the name of a storage node in Embodiment 1.

FIG. 22 shows the configuration of a message of registering a member ina discovery domain in Embodiment 1.

FIG. 23 is a flowchart of processing to delete the setting of LUNmasking in Embodiment 1.

FIG. 24 shows the configuration of a message of deleting a member from adiscovery domain in Embodiment 1.

FIG. 25 shows the configuration of a management server 2000 inEmbodiment 2.

FIG. 26 shows the configuration of a storage device table 2025 inEmbodiment 2.

FIG. 27 shows the configuration of a volume name table 2045 inEmbodiment 2.

FIG. 28 shows the configuration of a port name table 2050 in Embodiment2.

FIG. 29 is a flowchart of initial registration processing in Embodiment2.

FIG. 30 is a flowchart of volume creation processing in Embodiment 2.

FIG. 31 is a flowchart of volume deletion processing in Embodiment 2.

FIG. 32 is a flowchart of LUN creation processing in Embodiment 2.

FIG. 33 is a flowchart of LUN deletion processing in Embodiment 2.

FIG. 34 is a flowchart of reregistration processing in Embodiment 2.

FIG. 35 shows the configuration of a message of reregistration inEmbodiment 2.

FIG. 36 shows the configuration of are registration table in Embodiment3.

FIG. 37 shows the configuration of an SLP Directory Agent server inEmbodiment 3.

FIG. 38 shows the configuration of a service table in Embodiment 3.

FIG. 39 is a flowchart of initial registration processing in Embodiment3.

FIG. 40 shows the configuration of a message of initial registration inEmbodiment 3.

FIG. 41 is a flowchart of LUN creation processing in Embodiment 3.

FIG. 42 shows the configuration of a message of deleting a LUN inEmbodiment 3.

FIG. 43 is a flowchart of LUN deletion processing in Embodiment 3.

FIG. 44 is a flowchart of processing the additional setting of LUNmasking in Embodiment 3.

FIG. 45 is a flowchart of processing to delete the setting of LUNmasking in Embodiment 3.

FIG. 46 is a flowchart of reregistration processing in Embodiment 3.

FIG. 47 shows the configuration of a memory 4015 in Embodiment 4.

FIG. 48 shows the configuration of a storage device table 2025 inEmbodiment 4.

FIG. 49 is a flowchart of initial registration processing in Embodiment4.

FIG. 50 is a flowchart of management program processing in Embodiment 4.

FIG. 51 is a flowchart of reregistration processing in Embodiment 4.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Embodiments (1 through 4) will be described below with reference to theaccompanying drawings.

Embodiment 1

In this embodiment having a system configuration in which information onhost computers and disk arrays (storage systems) connected by an IPnetwork is managed in the database of an iSNS server, when a managementserver alters the configuration of storages, the alteration of the diskarray configuration is caused to be reflected in the contents registeredin the iSNS by use of the function of the disk array and the managementserver to communicate with the iSNS.

(1) System Configuration

FIG. 1 shows the overall configuration of a system to which Embodiment 1is applied.

This system comprises an iSNS server 1000, a management server 2000,host computers 3000 and 3005, a disk array 4000, and LAN cables 3015,3020, 3025, 3030, 3035, 3040 and 3045 constituting a network forconnecting the foregoing, and a LAN switch 3010.

The iSNS server 1000 is connected by a LAN interface 1010 to a LAN, hasan information database managed by the iSNS server, and provides afunction that is defined by the specifications of the iSNS. Inaccompanying drawings, those parts which relate to functions andoperations relevant to the purport of Embodiment 1 are illustrated.

In a memory 1015 is stored an iSNS server program 1020 for realizing thefunctions of the iSNS server. In a database 1060 are stored an entitytable 1025, a storage node table 1030, a portal table 1035, a portalgroup table 1040 and a discovery domain table 1045. A CPU 1005 executesthe iSNS server program 1020. The items of information stated in varioustables which the iSNS server 1000 has in the database 1060 are definedby the specifications of the iSCSI and the iSNS. Incidentally, though itwas stated that these tables 1025 through 1045 were registered in thedatabase 1060, they may as well be stored in the memory 1015.

The configurations of these tables will be described below.

The entity table 1025, which manages iSCSI devices in the network, hasthe configuration shown in FIG. 5. Column 102500 of entity IDs recordsthe entity identifier (entity ID) assigned uniquely to each of devices.The devices here mean hardware items connected to the network includinghost computers, disk arrays and servers, each assigned its own ID.Column 102505 of portal indexes records by portal index the portal whicheach device has. Similarly, column 102510 of storage node indexesrecords, by iSCSI node index, the storage node which each device has.

The storage node table 1030, which manages storage nodes in the network,has the configuration shown in FIG. 6. Column 103000 of storage nodeindexes, column 103005 of iSCSI names, column 103010 of types, andcolumn 103015 of aliases respectively record iSCSI node indexes each ofwhich is uniquely allocated to a storage node, iSCSI names which arecharacter strings each uniquely allocated, iSCSI node types eachrepresenting a node type, and iSCSI aliases as names more understandableto humans than iSCSI names.

The portal table 1035, which manages iSCSI portals in the network, hasthe configuration shown in FIG. 7. Column 103500 of portal indexes,column 103505 of IP addresses, column 103510 of TCP port numbers, column103515 of symbolic names, column 103520 of ESI ports and column 103525of ESI intervals respectively record portal indexes each of which is anumber uniquely allocated to a portal, portal IP addresses and portalTCP/UDP ports each allocated to the network interface of a portal,portal symbolic names used as names readily understandable by humans,port numbers of ESI message reception, and the shortest limit of theintervals of ESI message reception.

The portal group table 1040, which manages portal groups representingthe matches between storage nodes and the portals used by the respectivenodes, has the configuration shown in FIG. 8. Column 104000 of portalgroup indexes, column 104005 of storage node indexes, column 104010 ofportal indexes, and column 104015 of portal group tags (PGTs)respectively record portal group indexes each of which is a numberuniquely allocated to a portal group, storage node indexes (iSCSI nodeindexes) and portal indexes of the storage nodes and the portalsconstituting each portal group, and portal group tags (PGTs)representing relationships between portal groups. In a given storagenode, the presence of portals included in a portal group having the samePGT means capability of coordinated and parallel transmission/receptionof data. If a given combination of a storage node and a portal is notregistered in the portal group table 1040, it will mean the storage nodecannot be accessed via that portal.

The discovery domain table 1045, which manages discovery domainsrepresenting groups of mutually discoverable storage nodes, has theconfiguration shown in FIG. 9. Column 104500 of discovery domain IDs andcolumn 104505 of storage node indexes respectively record discoverydomain IDs each of which is an identifier uniquely allocated to adiscovery domain and iSCSI node indexes representing storage nodesbelonging to each discovery domain.

In a control node table 3050 are recorded the iSCSI names of nodes whichthe iSNS server 1000 is permitted to access as control node. In thisembodiment, the iSCSI name (Mng_Name) 2030 of the management server issupposed to be recorded in advance.

Now referring back to FIG. 1, the management server 2000 has a functionto manage storage devices, is connected to a LAN via a LAN interface2010. In a memory 2015 are stored a storage device table 2025 in whichinformation on storage devices to be managed, namely the disk array4000, the iSCSI name 2030 which records the management server's owniSCSI Name (Mng_Name), and a management program 2020 which stores aniSNS address 2035 recording the IP address of the iSNS server andprovides a storage management function. A CPU 2005 executes thismanagement program 2020. Further, as user interfaces for enabling themanager to perform operations, there are an output device 2080 and aninput device 2090.

The management program 2020 has the function of an iSNS client tocommunicate with the iSNS server 1000 by the iSNS Protocol defined bythe specifications of the iSNS. It communicates with the disk array 4000by a protocol unique to the disk array, and transmits or receives arequest for altering the configuration and its result. Details of theoperations of the management program will be described afterwards.

The storage device table 2025, which manages a storage device 4000within the network, such as a disk array, has the configuration shown inFIG. 2. Thus, column 202500 of device IP addresses, column 202505 of TCPport numbers and column 202510 of entity IDs respectively record the IPaddress and the port number used by each storage device forcommunication with the management program, and the entity identifier(entity ID) of each device.

Each of the host computers 3000 and 3005 (hereinafter only the hostcomputer 3000, representing both, will be mentioned), though theirinternal configuration will not be illustrated, has a LAN interface foruse in connection to the network, a memory for storing an applicationprogram for using the disk volumes provided by the disk array, and a CPUEor executing that program. The host computer 3000 further has an iSCSIname necessary for communication with the disk array 4000 by the iSCSIProtocol.

The disk array 4000 communicates with the host computer 3000 by theiSCSI Protocol via LAN interfaces 4030, 4035 and 4040, and a diskcontroller 4010 provides disk volumes 4020 and 4025 (hereinafter onlythe disk volume 4020, representing both, will be mentioned unless theother is specified) for controlling data reading and writing.Incidentally, the term “disk volume” refers to a virtual recording areaformed on a real storage area the disk array has. Hereinafter diskvolume may be called volume.

In a memory 4015 are stored an entity ID 4050 for recording the entityidentifier (Array_ID) of the disk array 4000, a port table 4055, avolume table 4060, an iSNS address 4065 for recording the address of theiSNS server, and an ESI interval 4070 for recording the transmissioninterval (T_e) of the message of the entity status inquiry (ESI) issuedby the iSNS server. The memory 4015 also holds a disk array controllerprogram 4045 for controlling the operations of the whole disk array, andthe program 4045 is executed by a CPU 4005.

The port table 4055, as shown in FIG. 3, has a configuration formanaging the ports (LAN interfaces) which the disk array 4000 has. Thuscolumn 405500 of port IDs, column 405505 of IP addresses, column 405510of TCP port numbers and column 405515 of ESI port numbers respectivelyrecord unique identifiers (e.g. 1-A) each allocated to a port, IPaddresses (e.g. IP_Addr_1) and port numbers (e.g. TCP_1) which the portsfor iSCSI communication, and port numbers (e.g. ESI_1) of reception ofESI messages from the iSNS.

The volume table 4060, as shown in FIG. 4, has a configuration formanaging the disk volumes provided by the disk array 4000, the hostcomputer 3000 which permits access to them, and the ports for use inaccessing the disk volumes. Column 406000 of volume IDs, column 406005of iSCSI names, column 406010 of port IDs, column 406015 of PGTs, column406020 of LUNs and column 406025 of allocated hosts respectively recordunique identifiers (e.g. Vol. 1) and iSCSI names (e.g. Name_V1) eachallocated to a disk volume, port IDs (e.g. 1-A) that can be used foraccessing disk volumes, portal group tags (e.g. “1”) of portal groupsconsisting of disk volumes and ports, LUNs (e.g. “1”) one of which aport to which a disk volume is allocated has, and iSCSI names (e.g.Name_H1) of host computers accessible via allocated ports.

The disk array controller program 4045 receives a request for alteringthe configuration by communicating with the management server 2000 by aprotocol unique to the disk array 4000 and creates or deletes diskvolumes or LUNs in addition to the processing of data transfers betweenthe host computer 3000 and the disk volume 4020 by use of the iSCSIProtocol. When creating a volume, it allocates a volume ID and an iSCSIname to the created volume. It also has a LUN masking function to limitaccess from the host computer 3000 according to information on theallocated host designated for each LUN and a function to set LUN maskingto alter the list of the host computer 3000 for permitting access. Itfurther has an iSNS client function to receive and respond to ESImessages.

Next will be described, with reference to flowcharts, operations in theabove-described configuration including processing for initialregistration of storage device management information, processing tocreate and delete disk volumes, processing to create LUNs, andprocessing for additional setting and deletion of LUN masking. Thesesequences of processing are achieved by executing the management program2020 of the management server 2000.

(2) Initial Registration

Further in this Embodiment 1, when a storage device whose disk volumeand LUN are already defined, such as an existing disk array, is to beadded to the objects of management, the management program 2020registers a storage node and a portal in the iSNS server 1000. Theseoperations will be described with reference to the flowchart of FIG. 10.

The address and the port number at which the additional disk arraytransmits and receives the request for operation from the managementprogram 2020 are supposed to be registered in advance by the manager inthe storage device table 2025. It is further supposed that the entity ID4050 and the ESI interval 4070 of the additional disk array are definedin advance.

First the manager selects the address and the port number of the diskarray to be additionally registered from the storage device table 2025by manipulating the input device 2090, and instructs the managementprogram 2020 to start the operation for initial registration (step10000). Then, using the selected address, the management programcommunicates with the disk array, and acquires from that disk array theentity ID 4050, the port table 4055, the volume table 4060 and the ESIinterval 4070 (step 10005). The acquired entity ID is recorded in theentity ID column of the storage device table 2025 (step 10010). Next,the management program 2020 sends the IP address registered at the iSNSaddress 2035 to the disk array, and requests its registration at theiSNS address 4065 (step 10015). In the disk array, usually this requestis executed and the IP address is registered at the ISNS address 4065.The management server 2000 determines whether or not the request hasbeen successfully executed by assessing the response to the request(step 10020) and, if unsuccessful, will end the processing of initialregistration by displaying the error on the output device 2080 (step10055).

If the requested registration is successfully executed, then thecontents of the port table 4055 received at step 10005 are transmittedfrom the management program 2020 to the iSNS server 1000, and areregistered in the portal table 1035 (step 10025). This registrationprocessing is executed by communication with the address registered atthe iSNS address 2035 by the communication protocol conforming to theiSNS specifications.

More specifically, a device attribute registration request (DevAttrReg)message 11000 by the iSNS Protocol as shown in FIG. 11 is created, andtransmitted to the iSNS server. In the Header part of the message,DevAttrReg is designated as the function ID 11005, an iSNS client flag11010 indicating that the sender is an iSNS client is set, and a replaceflag 11015 indicating deletion of the existing contents of the object ofregistration is set. In the Source Attribute part representing thesender, the iSCSI name of the management server (Mng_Name) 2030 isdesignated as the iSCSI name 11020. In the Message Key Attributes partrepresenting the object of registration, the entity ID received at step10005 is designated as the entity ID 11025 of the disk array to beregistered. In the Operating Attributes part, the entity ID 11030 of thedisk array and the communication protocol (iSCSI) 11035 of the diskarray are designated. Further, for each of the ports which the diskarray has, the Portal IP Address11040, Portal TCP/UDP Port11045 andPortal Symbolic Name11050 of the portal, and for the ESI Port 11060 theIP address 405505, TCP port number 405510, port ID 405500 and ESI portnumber 405515 of the port recorded in the port table acquired at step10005, are designated. In the Entity Status Inquiry Interval 11055 part,the ESI interval acquired at step 10005 is designated. Information itemsfrom 11040 through 11060 are designated for each port with the operatingattributes of the DevAttrReg message (from 11065 onward). Incidentally,though details are not shown in FIG. 11, each attribute consists, inaccordance with the specifications of iSNS, of the combination of anattribute tag denoting the type of the attribute, an attribute lengthand an attribute value of the attribute to be registered, and is alignedat the boundary of four bytes.

Now referring back to FIG. 10, the management program 2020 receives adevice attribute registration response (DevAttrRegRsp), which is aresponse from the iSNS server to a DevAttrReg message, and determineswhether or not the registration has been successfully accomplished (step10030).

If successful, the process advances to step 10035 to select one diskvolume from the acquired volume table 4060, a DevAttrReg message asshown in FIG. 12 is created from information registered in the volumetable and registered in the iSNS server (step 10040).

In FIG. 12, the Header, Source Attribute and Message Key Attributesparts (12005 through 12025) are the same as in the case of portalregistration except that the replace flag of the header is not set. Inthe Operating Attributes part, the iSCSI name 406005 of the disk volumeto be recorded is designated as the iSCSI name 12030 of the storagenode, the target as the iSCSI node type 12035, and the volume ID 406000as the iSCSI node alias 12040. Further, in order to register as a portalgroup the combination of the disk volume to be registered and theallocated port, PGT 406015 is designated as the portal group tag 12045.As the PG portal IP address 12050 and the PG portal TCP/UDP port 12055,the IP address 405505 and the TCP port number 405510 of the portmatching a port ID recorded at the port ID 406010 are respectivelydesignated. For the ports allocated to the disk volume to be registered,information items from 12045 through 12055 are designated (from 12060onward). However, for ports whose PGT 406015 values are the same, onlythe information on the PG portal IP address and the PG portal TCP/UDPport will continue to be designated with the designation of the portalgroup tag being used in common.

Referring to the flowchart of FIG. 10, a DevAttrRegRsp message isreceived from the iSNS server 1000 (step 10045) and, if registrationfails, the process will advance to step 10055. If registration issuccessful, processing from step 10035 through 10045 will be repeatedfor every disk volume recorded in the volume table 4060 (step 10050).

Next will be briefly described the operation by the iSNS server program1020 having received an iSNS message from the management server 2000registers in the iSCSI server 1000 the acquired relevant information inan iSNS database 1060.

The iSNS server program 1020, having received DevAttrReg message 11000(FIG. 11) to register a portal, additionally registers entity identifier11030 designated by the message in column 102500 of entity IDs in theentity table 1025. It also additionally registers the portal IP address11040, portal TCP/UDP port 11045, portal symbolic name 11050, ESIinterval 11055 and ESI Port 11060 of the designated portal in therespectively corresponding columns in the portal table 1035, andallocates a unique portal index to the portal. It further additionallyregisters the allocated value of the portal index in column 102505 ofportal indexes in the entity table 1025. If there are a plurality ofportals to be registered, information of and after 11065 will besimilarly registered.

Or having received a DevAttrReg message 12000 (FIG. 12) to register astorage node, the iSNS server program 1020 additionally registers theiSCSI name 12030, iSCSI node type 12035 and iSCSI Node Alias 12040 ofthe designated storage node in the respectively corresponding columns inthe storage node table 1030, and allocates a unique storage node indexto the storage node. It also additionally registers the value of theallocated storage node index in column 102510 of storage node indexes inthe entity table 1025. It further additionally registers, in the portalgroup table 1040, the portal index of the portal designated by the PGportal IP address 12050 and PG portal TCP/UDP Port 12055 and the storagenode index of the storage node designated by the iSCSI Name 12030,records the value of the portal group tag 12045 in column 104015 ofPGTs, and allocates a unique portal group index to the portal group. Ifthere are a plurality of portal groups to be registered, information ofand after 12060 will be similarly recorded.

The items of information on the disk array configuration added asobjects of registration in the sequence of processing described abovecan be reflected in the database 1060 of the iSNS server 1000.Incidentally, as the operations according to the iSNS server program1060 conform to the specifications of iSNS, no further details will begiven in this respect in the following description.

(3) Creation and Deletion of Disk Volume

The method of causing any change in the configuration of a disk array bycreating or deleting a disk volume in or from it to be reflected in thedatabase of the iSNS server will be described below.

First will be described the operations of the management program 2020with reference to the flowchart of FIG. 16. FIG. 16 shows generaloperations of the management program which take place when a disk volumeis created or deleted or a LUN is created or deleted.

When a volume is to be created, the manager selects, from the storagedevice table 2025, the disk array to be added by manipulating the inputdevice 2090, and instructs the management program 2020 to create a diskvolume (step 16000). When creating a volume, there is no need to acquirethe port table 4055 or the volume table 4060. When a volume is to bedeleted, the volume table 4060 is acquired to select the disk volume tobe deleted (step 16005). When creating a volume, the manager specifiesthrough the input device 2090 parameters needed for volume creation,including the size, and instructs the management program 2020 to createa disk volume (step 16010). When deleting a volume, the manager selects,from the acquired volume table 4060, the disk volume to be deleted, andinstructs the management program 2020 to delete the disk volume.

The management program 2020 requests the disk array 4000 to create ordelete the specified disk volume (step 16015). The disk array 4000executes the request processing and returns a response. The managementprogram 2020, if the received response indicates an error (step 16020),will display an error on the output device 2080 (step 16030) and end theprocessing. Or if the response indicates a success, it will display asuccess on the output device 2080 (step 16025) and end the processing.

Next will be described the operations of the disk array controllerprogram 4045 of the disk array 4000 with reference to the flowchartshown in FIG. 13. FIG. 13 shows general operations of the disk arraycontroller program which take place when a disk volume is created ordeleted or a LUN is created or deleted.

Upon receiving from the management program 2020 parameters needed forknowing the contents of and executing the configuration change (step13000), the disk array controller program determines whether or not theoperation is possible (step 13005) and, if impossible, will proceed tostep 13040. If possible, it will execute the requested operation (step13010), and record the result of the operation in, and thereby update,the volume table 4060 (step 13015).

For instance if it is requested to create a volume, the program willcreate a disk volume on the basis of the parameters specified by themanager, allocate to it a volume ID and an iSCSI name, and add them tothe volume table 4060. It records a sign indicating the absence ofregistration in any other column of the volume table 4060. Or when avolume is to be deleted, it deletes the disk volume selected by themanager and the pertinent row in the volume table 4060.

Next, the program selects one port from the port table 4055 (step13020), and transmits from that port a message requesting the iSNSserver 1000 to update the registered contents (step 13025).

When a volume is to be created, a DevAttrReg message 14000 shown in FIG.14 is created and transmitted to the iSNS server 1000. While the meaningof each attribute is the same as in the registration of a storage nodein initial registration, the iSCSI name of the volume created as aniSCSI name 14020 is designated in the Source Attribute part unlike inregistration from the management server 2000. In the OperatingAttributes part are designated the iSCSI name 14030 of the createdvolume, the target as the type 14035 of the storage node, and the volumeID allocated as the iSCSI alias 14040.

When a volume is to be deleted, a device deregister request (DevDereg)message 15000 as shown in FIG. 15 is transmitted. In the DevDeregmessage reflecting volume deletion, no message key attribute isdesignated, but a source attribute 15015 and, in the OperatingAttributes 15020 part, the iSCSI name of the disk volume to be deletedas the iSCSI name are designated.

The disk array controller program 4045, receiving a responseDevAttrRegRsp or DevDeregRsp to the DevAttrReg message 14000 or theDevDereg message 15000 from the iSNS server 1000, determines whether ornot the registration attempt has been successful (step 13030). As aresult of the determination, if successful, a response of success willbe transmitted to the management program 2020 of the management server2000 (step 13045), and the processing will be ended. Or if unsuccessful,another port will be selected and the registration request will berepeated (step 13035). If the registration attempt fails at every port,a response of error will be transmitted to the management program 2020and the processing will be ended (step 13040).

As described above, any change in configuration due to the creation ordeletion of a disk volume can be reflected in the database 1060 of theiSNS server 1000 by the processing of the disk array controller program4045 of the disk array 4000.

(4) Creation and Deletion of LUN

When a LUN is to be created, the management program 2020 acquires thevolume table 4060 and the port table 4055 at step 16005 in FIG. 16. Themanager selects a disk volume and a port for creating the LUN from therespective tables by manipulating the input device 2090, and designatesthe value and the port group tag of the LUN to be allocated (step16010). When a LUN is to be deleted, the volume table 4060 is acquiredat step 16005 and the LUN to be deleted is selected (step 16010).

Further regarding the operations of the disk array controller program4045 for the disk array, when a LUN is to be created, the selected portID is added at step 13015 in FIG. 13 to the row representing theselected disk volume in the volume table 4060, and the designated PGTand LUN are registered. Or when a LUN is to be deleted, the registeredport ID and PGT representing the selected LUN are deleted from thevolume table 4060. It has to be noted, however, that the deleted port IDis recorded elsewhere in the memory because it will be required when amessage conforming to the iSNS Protocol is to be created.

Further at step 13025, a DevAttrReg message shown in FIG. 17 is created,and transmitted to the iSNS server 1000. In the Source Attribute part isdesignated the iSCSI Name 17020 of the disk volume to which the LUN tobe worked on is allocated. When a LUN is to be created, in the OperatingAttributes part are designated the iSCSI name 17030 of the selected diskvolume, the designated portal group tag 17035, and the IP address 17040and port number 17045 of the selected port.

Or when a LUN is to be deleted, the iSCSI name 17030 of the disk volumeof the selected LUN, and the IP address 17040 and port number 17045 ofthe port of the selected LUN are designated. For the portal group tag17035, 0 is designated as the attribute length to indicate that thestorage node designated in the message cannot be accessed via thedesignated portal. The iSNS server program 1020 having received aDevAttrReg message containing a portal group tag whose attribute lengthis “0” deletes the registration of the pertinent portal group from theportal group table 1040.

As described above, any change in configuration due to the creation ordeletion of a disk volume can be reflected in the database 1060 of theiSNS server 1000 by the operations of the disk array controller program4045 of the disk array 4000.

(5) Addition and Deletion of Setting of LUN Masking

When LUN masking is to be set, the disk volume and the host computerwhich was allocated it should belong to the same discovery domain. Orwhen the setting of LUN masking is deleted and accessing of the diskvolume by a certain host computer is forbidden, it is desirable for thedisk volume to be deleted from the discovery domain so that the hostcomputer cannot discover the disk volume. Since a discovery domain canbe worked upon only from a control node registered in the iSNS server1000, the registration is altered by transmitting a message by the iSNSProtocol from the management program 2020.

The operations of the management program to additionally register a hostcomputer to permit access to a certain LUN will now be described withreference to the flowchart of FIG. 18.

First the manager selects the disk array to be worked on from thestorage device table 2025 by manipulating the input device 2090, andinstructs the management program 2020 to additionally set LUN masking(step 18000). The management program acquires the volume table 4060 fromthe selected disk array (step 18005). The manager selects from thevolume table the disk volume and the LUN which are the objects of LUNmasking by manipulating the input device 2090 (step 18010).

Next, whereas the manager has to select the host computer which is to bepermitted to access, in this embodiment, first a list of host computersbelonging to the same discovery domain as the selected disk volume isdisplayed on the output device 2080 to show it to the manager (steps18015 through 18050) and, if the manager instructs selection fromoutside the discovery domain (step 18055), the list of all the hostcomputers is shown (steps 18060 through 18065) to let the manager tomake selection (step 18070).

At step 18015, the device attribute query request (DevAttrQry) messageshown in FIG. 19 is transmitted to the iSNS server 1000, and a list 1045of the discovery domain IDs (DD_ID) of the selected disk volume isacquired. In the Message Key Attribute part is designated the iSCSI Name19020 of the selected disk volume, and in the Operating Attributes partthe discovery domain ID, which is the attribute desired to be acquired,is designated with the attribute length 19025 being “0”. As a responsefrom the iSNS server 1000, a device attribute query response(DevAttrQryRsp) including a list of DD IDs is received.

One of the acquired DD_IDs is selected (step 18020), the DevAttrQrymessage shown in FIG. 20 is transmitted to the iSNS server 1000, and thename of that domain and a list of storage nodes included as members areacquired (step 18025). In the Message Key Attributes part, the selectedDD_ID 20020 is designated while in the Operating Attributes part aredesignated DD_Symbolic Name and DD_Member iSCSI Name, which are theattributes desired to be acquired, with the attribute length 19025 being0.

Further, one of the acquired storage nodes is selected (step 18030), theDevAttrQry message shown in FIG. 21 is transmitted to the iSNS server,and the node type and name of the acquired node are acquired (step18035). In the Message Key Attributes part is designated the iSCSI name21020 of the selected storage node, and in the Operating Attributes partare designated the iSCSI node type 21025 and iSCSI alias 21030, whichare the attributes desired to be acquired with the attribute length19025 being “0”. This is repeated on all the nodes (step 18040) and onall the discovery domains acquired at step 18015 (step 18045).

At step 18050, the manager displays a list of the iSCSI names and thenames (iSCSI aliases) of members whose initiators are the names and nodetypes of the domain for each of the discovery domains acquired on theoutput device 2080 as available alternatives of host computers forsetting LUN masking. If the manager instructs to select a host computerfrom outside that list (step 18055), the same processing as at steps18015 through 18045 will be performed at step 18060. It has to be noted,however, that the DevAttrQry message created at step 18015, shown inFIG. 19, is to acquire at step 18060 all the discovery domains in theiSNS database without designating any message key attribute. At step18065, the list of items of information on all the acquired hostcomputers is displayed on the output device 2080.

The manager selects, from the list displayed on the output device 2080,the host computer 3000 on which LUN masking is to be set by manipulatingthe input device 2090, and instructs the management program 2020 to setLUN masking (step 18070). The management program 2020 requests the diskarray 4000 to set LUN masking (step 18075). It determines from theresponse returned from the disk array 4000 whether or not the settingattempt has been successful (step 18080). As a result of thedetermination, if unsuccessful, an error message will be displayed onthe output device 2080, and the processing will be ended (step 18110).

Or if successful, the disk volume and the host computer on which LUNmasking has been set should belong to the same discovery domain. At step18085, the manager selects whether they should belong to any existingdiscovery domain or to a newly created domain. If they are to belong toan existing domain, the manager will select one from the list ofdiscovery domains acquired at step 18015 or step 18060 (step 18090). Orif a new discovery domain is to be created, the manager will specify itsname from the input device 2090 (step 18095).

At step 18100, a DD register (DDReg) message shown in FIG. 22 is createdand transmitted to the iSNS server 1000. Where an existing domain hasbeen selected, in the Message Key Attributes part will be designated theDD_ID of the domain selected as DD_ID 22020. Or where a new domain is tobe created, nothing will be designated in the Message Key Attributespart. In the Operating Attributes part, the name of the existing domainor a name designated by the manager as the name of the newly createddomain is designated as the DD_Symbolic Name 22025. Also, the iSCSInames of the disk volume and of the host computer are designated as theiSCSI names 22030 and 22035 representing members of the discoverydomain.

Next will be described the operations of the management program 2020when the host computer to permit access to a certain LUN is to bedeleted with reference to the flowchart of FIG. 23. In FIG. 23, steps23000 and 23005 are respectively similar to steps 18000 and 18005 inFIG. 18.

At step 23010, the list of host computers allocated to the LUNs of thevolumes recorded in the acquired volume table is displayed on the outputdevice 2080 as available alternatives of the objects of deletion. Themanager selects a combination of volume, LUN and host computer from thelist displayed on the output device 2080 as the setting of LUNmasking tobe deleted, and instructs the management program 2020 to delete thesetting of LUN masking (step 23015). The management program 2020requests the disk array 4000 to delete the setting of LUN masking (step23020). It then determines from the response returned from the diskarray 4000 whether or not the setting deletion has been successful (step23025) and, if unsuccessful, will display an error message on the outputdevice 2080 and end the processing (step 23065).

Or if successful, with the acquired volume table displayed on the outputdevice 2080 being referenced, it will be checked whether or not theselected disk volume is allocated to the selected host computer at anyport and, if it is allocated to any port, the processing will be ended(step 23030). If the selected host computer is allocated to no port, thedisk volume can be deleted from the list of members of the discoverydomain to which the host computer belongs because that host computerneed not discover the selected disk volume. Whether or not to actuallydelete it is specified by the manager and, if non-deletion is opted for,the processing will be ended (step 23035).

If it is to be deleted, the DevAttrQry message shown in FIG. 19 will betransmitted to the iSNS server 1000, and a list of discovery domains towhich the host computer belongs will be acquired. In the Message KeyAttributes part will be designated the iSCSI name of the host computer.One of the acquired discovery domains is selected (step 23045), the DDDeregister (DDDreg) message shown in FIG. 24 will be created at step23050, and it is transmitted to the iSNS server. In the Message KeyAttributes part is designated the DD_ID 24020 of the selected discoverydomain. In the Operating Attributes part is designated the iSCSI name24025 of the disk volume to be deleted from the members of the discoverydomain. Steps 23045 and 23050 are repeated on every one of the discoverydomains acquired at step 23040 (step 23055) and, if any deletion requestfails (step 23060), the processing will be ended with an error messagedisplayed (step 23065).

As described above, by the operations executed by the management program2020, it is possible to alter the configuration of discovery domainsmanaged by the database 1060 of the iSNS server 1000, interlocked withconfigurational changes resulting from the creation or deletion of LUNmasking.

This Embodiment 1 enables configurational changes in storage devicesresulting from the addition of any disk array, creation or deletion ofany volume, or creation or deletion of any LUN to be reflected inregistration in the database of the iSNS server 1000. It also enablesthe configuration of any discovery domain to be altered, interlockedwith configurational changes resulting from the creation or deletion ofLUN masking.

Embodiment 2

The system configuration of this embodiment is substantially similar tothat of Embodiment 1 shown in FIG. 1 except in the following respects.Thus, in Embodiment 2, the disk array controller program 4045 of thedisk array 4000 has no iSNS client function, and all the necessaryoperations on the iSNS server 1000 are performed by the managementprogram 2020 of the management server 2000. It further provides afunction to enable the manager to name any disk volume or port asdesired, and to register the names so given in the database of the iSNSserver 1000 as an iSCSI alias or a portal symbolic name.

The method of altering the setting LUN masking in this embodiment issimilar to that in Embodiment 1. Differences from Embodiment 1 will bedescribed in detail below.

(1) Configurations of Management Server and Disk Array

FIG. 25 shows the configuration of the management server 2000 in thisembodiment.

Referring to FIG. 25, the storage device table 2025 has a configurationshown in FIG. 26. Herein, in column 202510 of reregistration times arerecorded the next registration times for periodically reregistering thecontents of registration regarding various devices in the iSNS database.If “0” is entered in this column, the management program 2020 willperform no reregistration regarding that device (disk array). A clock2040 is a clock for informing the management program 2020 of the currenttime.

A volume name table 2045, which records matches between disk volumes andtheir respective names, has a configuration as shown in FIG. 27. Thus,column 204500 of volume IDs, column 204505 of entity IDs and column204510 of names respectively record the volume ID of the disk volume4020, the entity ID of the disk array 4000 which provides the diskvolume 4020, and the name which the manager assigned to the disk volume.A port name table 2050, also having a similar configuration to thevolume name table 2045 as shown in FIG. 28, records the matches betweendifferent ports and their names.

As the reregistration period, the period T_e of registration in the iSNSdatabase is recorded, and as the period margin 2060, a margin T_m forstarting reregistration processing not later than the reregistrationtime recorded in the storage device table 2025 is recorded. The valuesof T_e and T_m are supposed to be specified in advance by the manager.

The disk array controller program 4045 of the disk array 4000 in thisembodiment, unlike its counterpart in Embodiment 1, has no iSNS clientfunction. Accordingly, it has neither the iSNS address 4065 nor the ESIinterval 4070.

Incidentally in FIG. 25, illustration of the output device 2080 and theinput device 2090 is dispensed with.

Operations in this configuration including the processing of initialregistration of storage device management information, that of diskvolume creation and deletion, that of LUN creation and deletion, andreregistration processing will be described below with reference toflowcharts.

(2) Initial Registration

Initial registration in this embodiment, though substantially similar tothat in the procedure shown in FIG. 10, includes the assignment of namesby the manager to the disk volume and the port. As shown in FIG. 29, theprocedure between step 10005 and step 10025 in FIG. 10 is replaced bythe procedure between step 29010 and step 29020. At step 29010, anentity ID is recorded in the storage device table 2025, a volume ID andan entity ID are further recorded in the volume name table 2045, and aport ID and an entity ID are recorded in the port name table 2050.

Further, a volume ID and a port ID are recorded in the columns of namesin the volume name table 2045 and of the port name table 2050.

At step 29015, whether or not to edit names is selected by the managerby manipulating the input device 2090. In the case of editing names, themanager will record names designated for each disk volume and each portrespectively in the volume name table 2045 and the port name table 2050(step 29020). In the case of not editing names, the volume IDs and theport IDs recorded at step 29010 will remain as names.

At step 10025, a message in which a reregistration period T_r 2055 isdesignated as the registration period in addition to the operatingattributes shown in FIG. 11 is created and transmitted to the iSNSserver 1000. Further, the current time read from the clock 2040augmented with the registration period designated by a DevAttrRegRspmessage from the iSNS is registered in the row of reregistration timesin the storage device table 2025.

Since the disk array 4000 in this embodiment has no iSNS clientfunction, steps 10015 and 10020 in FIG. 10 are dispensed with. Theacquisition of an ESI interval at step 10005 is also dispensed with.

Not only in initial registration but in creating a message by the iSNSProtocol, as attributes for which port IDs or volume IDs were previouslyrecorded, such as the portal symbolic name 11050 in FIG. 11 or the iSCSIalias 12040 in FIG. 12, names recorded in the port name table and thevolume name table are registered. For the source attribute, the iSCSIname Mng_Name of the management server is designated.

(3) Creation and Deletion of Volume

In this embodiment, the disk array has no iSNS client function, but arequest for altering the storage configuration from the managementprogram 2020 is met within the disk array. Since the operationsregarding this part are similar to their counterparts in Embodiment 1unless otherwise stated expressly, operations of the management program2020 will be mainly described regarding this embodiment.

The operations of the management program in creating a volume will bedescribed with reference to the flowchart of FIG. 30.

As a response to the request to the disk array 4000 for volume creationat step 30005, if the creation is successful, the volume ID of the diskvolume created at step 30010 will be received. In the successful case,the volume table 4060 is received from the disk array 4000, and an iSCSIname and a volume ID matching the received volume ID are added to thevolume name table 2045 (step 30020). The volume ID is also recorded inthe column of names in the volume name table 2045. Further, the managerselects by manipulating the input device 2090 whether to edit the nameof the created disk volume (step 30025). If it is selected to edit thename, the name designated by the manager will be edited, and the editedname will be recorded in the volume name table 2045 (step 30030).

Then at step 30035, the DevAttrReg message shown in FIG. 14 is created,and transmitted to the iSNS server 1000. The created volume isregistered in the database 1060 of the iSNS server 1000. From step 30040onward, the processing is similar to that from 16020 onward in FIG. 16.

Next, the operations of the management program in deleting a volume willbe described with reference of the flowchart of FIG. 31.

Since it is impossible to acquire the iSCSI name of the deleted volumefrom the disk array 4000 after the volume 4020 is deleted, the volumetable 4060 is acquired at step 31005 before its deletion, and the iSCSIname of the disk volume is acquired in advance. If the volume issuccessfully deleted, the record on the deleted disk volume will bedeleted from the volume name table 2045 (step 31020).

At step 30025, the DevDereg message shown in FIG. 15 is created andtransmitted to the iSNS server 1000.

These executions of the management program 2020 enable changes inconfiguration due to the creation or deletion of any disk volume to bereflected in the database 1060 of the iSNS server 1000.

(4) Creation or Deletion of LUN

The operations of the management program to create a LUN will bedescribed below with reference to the flowchart of FIG. 32.

First, the manager manipulates the input device 2090 to select a diskvolume and a port for creating a LUN from the volume name table 2045 andthe port name table 2050 (step 32005). It further specifies the valueand PGT of the LUN and instructs the management program 2020 to createthe LUN. The management program 2020 requests the disk array 4000 tocreate the LUN (step 32010). Based on the determination of success orfailure of LUN creation on the disk array, if the LUN creation provessuccessful, the volume table 4060 and the port table 4055 will beacquired from the disk array 4000, and the iSCSI name of the selectedvolume and the IP address and port number of the port will be acquired(step 32020). Then the DevAttrReg message shown in FIG. 17 is createdand transmitted to the iSNS server 1000 (step 32025).

Next will be described the operations of the management program 2020 todelete a LUN with reference of the flowchart of FIG. 33.

At step 33005, the volume table 4060 is acquired from the disk array4000. The manager manipulates the input device 2090 to select from thevolume table the LUN to be deleted, and instructs the management program2020 to delete the LUN (step 33010). If volume deletion on the diskarray 4000 proves successful (step 33020), the DevAttrReg message shownin FIG. 17 will be created and transmitted to the iSNS server 1000 (step33025). The LUN deletion processing by the iSNS server 1000 is the sameas described above. These executions of the management program 2020enable changes in configuration due to the creation or deletion of anyLUN to be reflected in the database 1060 of the iSNS server 1000.

(5) Reregistration

Since in this embodiment the disk array has no iSNS client function andno response to the ESI message issued by the iSNS server is possible,reregistration is periodically made in the database 1060 of the iSNSserver 1000. Unless reregistration is made, any registered item havingpassed the specified registration period is deleted from the database1060. The management program 2020 processes reregistration in thebackground besides performing usual management processing. Executions inthe background are accomplished by use of multiprocess or multithread.

The operations of reregistration processing performed by the managementprogram 2020 will now be described with reference to the flowchart ofFIG. 34.

At step 34000, one device whose reregistration time is not “0” isselected from the storage device table 2025. The current time t is readfrom the clock (step 34005) and, if the difference between thereregistration time and t stated in the storage device table 2025 isgreater than the period margin T_m (step 34010), the processing willreturn to step 34000 to select another device. If the difference is notgreater, the DevAttrReg message shown in FIG. 35 will be transmitted tothe iSNS server 1000, and the entity ID of the disk array will bereregistered (step 34015).

Although the message shown in FIG. 35 is a message simply designating anentity ID and a reregistration period, since all the storage nodebelonging to the same entity can be reregistered by any single messageaccording to the iSNS specifications, all the registered contentsregarding every device can be reregistered by this processing. If thereregistration attempt proves successful (step 34020), thereregistration period designated by the DevAttrRegRsp message sent as aresponse from the iSNS server 1000 augmented with the time acquired atstep 34005 will be recorded as the reregistration time in the storagedevice table 2025 (step 34025), and the processing will return to step34000. If the reregistration attempt proves unsuccessful, an errormessage will be displayed (step 34030), and the processing will returnto step 34000.

Information is periodically reregistered by these operations executed bythe management program 2020, and the registered contents can be therebymaintained so that they may not be deleted by the iSNS server program1020 as being outdated.

In this embodiment, even where the disk array controller program of thedisk array 4000 has no iSNS client function, the database of the iSNSserver 1000 can be updated. Further, names assigned to disk volumes orports by the management program 2020 of the management server 2000 canbe registered in the database of the iSNS server 1000 as iSCSI aliasesor port symbolic names.

Embodiment 3

This embodiment is an example of application to an environment in whichthe iSCSI device is managed by use of an SLP instead of an iSNS. In thisembodiment, a disk volume accessed by the iSCSI Protocol is registeredas a service in the directory agent (DA) of the SLP. Incidentally, themethod by which the SLP is used for discovering the iSCSI device issupposed to follow already proposed specifications, whose details willnot be described herein. The following description will mainly focus ondifferences from Embodiment 2.

(1) Configurations of SLP Directory Agent Server and Management Server

In this embodiment, the directory agent server of the SLP (SLP DA) willbe used instead of the iSNS server. Therefore, the management programhas a user agent function of the SLP instead of the iSNS client functionand an SLP DA address instead of the iSNS address 2035. Under managementusing the SLP, combinations of disk volume and port are registered asservices, but not as isolated port objects. Therefore, the managementserver in this embodiment, unlike that in Embodiment 2, does not havethe port name table 2050.

FIG. 37 shows the configuration of an SLP DA server 37000.

This SLP DA server 37000 is connected to the network via a LAN interface37010. Ina memory 37015 is stored a DA program 37020 which provides aservice table 37025, which is the database of services within thenetwork, and the functions of the DA. A CPU 37005 executes the DAprogram.

The service table 37025 has a configuration shown in FIG. 38.

Referring to FIG. 38, column 3702500 of URLs record the URLs ofregistered services. In an iSCSI device, a URL includes the IP addressand port number of the portal and the iSCSI name according to theproposed specifications. In column 3702505 of service types is recordedservice:iscsi:target in the case of a disk volume accessed by the iSCSIProtocol. In column 3702510 of a scope list are recorded one or morescopes to which services belong. In column 3702515 of lifetime isrecorded the duration of registration of each service. The DA programreads the current time from a clock 37030 to check whether or not thelifetime of a given service has expired and, if expired, deletes theservice. Column 3702520 of attributes and column 3702525 of attributevalues respectively record the combination of the attribute and itsvalue of each service.

The storage device table of the management server has the sameconfiguration as what is shown in FIG. 2. Further, the memory has withinit a reregistration table shown in FIG. 36. Referring to FIG. 36, column3602500 of URLs, column 3602505 of scopes, column 3602515 of attributesand column 3602520 of attribute values respectively record the samevalues regarding the services in the rows having the same names in FIG.37. Column 3602510 of reregistration times record the nextreregistration of each service. No service whose reregistration time “0”is reregistered.

(2) Initial Registration

The operations of the management program for initial registration inthis embodiment are substantially similar to those for Embodiment 2shown in FIG. 29. The following description will mainly focus on pointsof difference with reference to the flowchart of FIG. 39. At step 100005in FIG. 29, each of the LUNs recorded in the acquired volume table isrecorded in the reregistration table as a service in addition torecording in the storage device table and the volume name table.Matching relationships between items recorded in the volume table andthose to be recorded in the reregistration table will be describedafterwards. In the reregistration time column of the reregistrationtable is recorded “0”. At step 29020 in FIG. 39, in addition to names inthe volume name table, the list of scopes for the reregistration tableis also edited. DEFAULT is stated as the value in an unedited scopelist. At step 39000, one of the services recorded in the reregistrationtable is selected, and the current time is read out of the clock (step39005); at step 39010 the service registration (SrvReg) message shown inFIG. 40 is created and transmitted to SLP DA.

As the header of a SrvReg message 40000 is designated a function ID40005 representing the SrvReg message, and a fresh flag indicatingdeletion of previous registration regarding this service is set. In theURL Entry part, a reregistration period T_r is designated for a lifetime40015, and a URL recorded in the reregistration table for a URL 40020.URLs in the reregistration table are defined for each LUN of the diskvolumes recorded in the acquired volume table; the IP address and portnumber of the port for which the LUN is linked by a colon to followservice:iscsi:target://; and the iSCSI name of the disk volume isdesignated to follow/. As the service type 40025 is designatedservice:iscsi:target; as the scope list 40035 is designated the value ofthe scope list in the reregistration table; and as the attribute list40030 are designated attributes stated in the service template of theiSCSI target device. As attributes including the iscsi-name, auth-nameand portal-group, the combinations of attribute and attribute value inthe respective reregistration tables are designated, and matched withthe values of the iSCSI name, allocated host and PGT of the disk volumeof each LU recorded in the respective volume tables. As transports isdesignated tcp. As auth-cred and auth-addr is designated any. As aliasis designated the name to be recorded in the volume name table. Sincethe form of the attribute list is to conform to the specifications ofthe method of discovery of iSCSI devices by SLP, detailed descriptionwill be dispensed with.

If the registration attempt proves successful (step 39015), the timeacquired at step 39005 augmented with the reregistration period T_r isrecorded in column 3602510 of reregistration times in the reregistrationtable (step 39020). If unsuccessful, an error message will be displayed(step 39025). The processing from step 39005 through step 39025 isrepeated for all the services recorded in the reregistration table (step39030).

By the procedure described above, information on the configuration ofany disk array to be added as the object of registration can bereflected in the database held by the SLP DA server 37000. Incidentally,the operations of the SLP DA program are supposed to conform to thespecifications of SLP, and their description is dispensed with.

(3) Creation and Deletion of LUN

Since only accessible disk volumes to which ports are allocated areregistered as services in management using SLP, no processing forregistration in SLP arises with respect to volume creation and deletion,and only the internal configuration of the disk array is altered asusual.

The operations of the management program when a LUN is to be createdwill be described with reference to the flowchart of FIG. 41.

At step 41005, the volume table 4060 and the port table 4055 areacquired from the disk array 4000. The manager selects the volume andport for LUN creation, then specifies the values and scopes of the LUNand PGT, and instructs the management program to create the LUN. If theattempt to create the LUN fails (step 41010), an error message will bedisplayed on the output device and the processing will be ended (step41045).

If the LUN creating attempt proves successful, the current time will beacquired from the clock (step 41020), create the SrvReg message shown inFIG. 40, and transmit it to SLP DA. In this case, unlike in initialregistration, no fresh flag 40010 is set, and as the auth-name attributeis designated any. If the registration attempt proves successful (step41030), the registered attribute will be recorded in the reregistrationtable. Also, as in the processing of initial registration, thereregistration time is recorded, a success message is displayed, and theprocessing is ended (step 41035).

The operations of the management program when a LUN is to be deletedwill be described below with reference to the flowchart of FIG. 43.

At step 43005, the volume table 4060 is acquired from the disk array4000. The manager selects the disk volume, port and LUN of the LUN to bedeleted by manipulating the input device, and instructs the managementprogram to delete the LUN. Next, reregistration during the processing isprevented by setting to “0” the reregistration time of the service inthe reregistration table corresponding to the selected LUN (step 43010).If the attempt to delete the LUN fails (step 43020), an error messagewill be displayed on the output device and the processing will be ended(step 43040).

If the attempt proves successful, the service deregistration (SrvDereg)message shown in FIG. 42 will be created and transmitted to SLP DA (step43025). Referring to FIG. 42, as a scope list 42010 are designated thevalues recorded in the scope list in the reregistration table. As theURL 42015 in the URL Entry part, the value recorded as the URL in thereregistration table is designated. In the Tag List 42020, “0” isdesignated as the attribute length, and no attribute is designated. Ifthe deletion attempt proves successful (step 41030), the pertinentrecord will be deleted from the reregistration table, a success messagedisplayed, and the processing ended (step 41035).

These operations of the management program enable any change inconfiguration due to LUN creation or deletion to be reflected in thedatabase of the SLP DA server.

(4) Addition and Deletion of Setting of LUN Masking

Under management using the SLP, unlike in discovery domains of the iSNS,a list of the iSCSI names of accessible host computers is recorded asthe auth-name attributes of services. Therefore, when the setting of LUNmasking has been altered, the auth-name attribute of the servicerepresenting the pertinent disk volume has to be altered.

The operations of the management program in additional setting of LUNmasking will be described with reference to the flowchart of FIG. 44.

At step 44005, a volume table is acquired from the disk array, and themanager selects the volume, port and LUN for which LUN masking is to beset. The manager also designates the iSCSI name of the host computer tobe allocated, and instructs the management program to additionally setLUN masking (step 44010). The management program requests the disk arrayto set the designated LUN masking (step 44015) and, if the settingattempt fails (step 44020), an error message will be displayed on theoutput device and the processing will be ended (step 44045).

If successful, the iSCSI name of the host computer designated for theattribute value of the auth-name attribute of the reregistration tablewill be added (step 44025), and the SrvReg message shown in FIG. 40 willbe transmitted to SLP DA. However, the fresh flag 40010 is not set. Theauth-name attribute in the Attribute List 40030 part is designated avalue recorded as one of the attribute values of the auth-name in thereregistration table also including the iSCSI name of the additionalhost computer. If the registration attempt proves successful, a successmessage will be displayed and the processing will be ended (step 44040).

Next, the operations of the management program in deleting the settingof LUN masking will be described with reference to the flowchart of FIG.45.

As in the additional setting of LUN masking charted in FIG. 44, at step45010, an iSCSI name is selected from auth-name attributes in thereregistration table instead of designating the iSCSI name of the hostcomputer. At step 45025, the selected iSCSI name is deleted from theattribute values of the auth-name attributes. These operations of themanagement program enable any change in configuration due to theaddition or deletion of the setting of LUN masking to be reflected inthe database of the SLP DA server.

(5) Reregistration

The DA program deletes the registration of any service whose lifetimehas expired or reregisters it before expiration if the registeredcontents are to be retained.

The operations of reregistration processing performed by the managementprogram will be described below with reference to the flowchart of FIG.46.

At step 46000, one service whose reregistration time is not “0” isselected from the reregistration table. The current time t is acquiredfrom the clock (step 46005), and it is checked whether or not thereregistration time t recorded in the reregistration table is shorterthan the period margin T_m (step 46010). If it is longer, the processingwill return to step 46000 to select another service. If it is shorter,the SrvReg message shown in FIG. 40 will be created from the contentsrecorded in the reregistration table and transmitted to SLP DA (step46015). If the registration attempt fails (step 46020), an error messagewill be displayed (step 46030), and the processing will return to step46000. If successful, the time acquired at step 46005 augmented with T_rwill be recorded in the reregistration time of the reregistration table,and the processing will return to step 46000 (step 46025).

These executions of the management program enable information to beperiodically reregistered in the database of the SLP DA server andthereby to maintain the registered contents.

This Embodiment 3, in an environment in which the iSCSI device is to bediscovered by use of the SLP, enables changes in the configuration ofany storage device resulting from the creation or deletion of any volumeor the creation or deletion of any LUN to be reflected in registrationin the database held by the SLP DA server. Also, interlocked withconfigurational changes due to the creation or deletion of LUN masking,it enables the auth-name attribute of a service representing a diskvolume to be updated.

Embodiment 4

This embodiment represents an example in an environment in which storagedevices to be managed, described with reference to Embodiment 1 andEmbodiment 2, are in mixed existence. Thus, the embodiment is a systemin which both a disk array having the iSNS client function and a diskarray having no such function are present in mixture.

The management program 2020 determines whether or not the disk array4000 to be worked on has the iSNS client function, selects either themanagement method of Embodiment 1 or the management method of Embodiment2, and executes processing on it. The following description will mainlyfocus on differences from Embodiment 2.

(1) Configurations of Disk Array and Storage Device Table

Though only one disk array 4000 is shown in FIG. 1, in this Embodiment 4it is supposed that a disk array having the iSNS client function andanother disk array having no such function are connected to the LANswitch 3010 in any desired way. Incidentally, both disk arrays arereferred to by a sign 4000.

In this embodiment, the disk array 4000 to be managed has in its memory4015 an iSNS client flag 4075 as shown in FIG. 47 in addition to theconstituent elements 4045 through 4070 shown in FIG. 1. The flag has avalue of “TRUE” or “FALSE”, TRUE indicating that the disk array 4000 hasthe iSNS client function and FALSE indicating the absence of thatfunction.

Further as shown in FIG. 48, the storage device table 2025 of themanagement server 2000, unlike the storage device table shown in FIG.26, is assigned column 202520 of the iSNS client flag for recording thevalue of the iSNS client flag of each device.

(2) Initial Registration

The operations of the management program 2020 in initial registrationwill be described below with reference to the flowchart of FIG. 49.

Unlike at step 10005 for Embodiment 1 and 2 (FIG. 10 and FIG. 29,respectively), at step 49005 the management program 2020 also acquiresthe value of the iSNS client flag from the disk array 4000. Then itrecords this iSNS client flag in the storage device table 2025 (step49010). Next, it assesses the value of this flag and determines whetheror not the disk array 4000 to be managed has the iSNS client function(step 49015).

If the value of the flag is “TRUE”, namely if the disk array has theiSNS client function, processing for Embodiment 1 (steps 10010 through10020 in FIG. 10) will be performed (step 49020). Of if the value of theflag is “FALSE”, namely if the disk array has no iSNS client function,processing for Embodiment 2 (steps 29010 through 29020 in FIG. 29) willbe performed (step 49025). After that, steps of processing common toEmbodiments 1 and 2 (steps 10025 through 10055 in FIG. 10) will beperformed (step 49030).

(3) Change-Over of Contents of Processing

The operations of the management program 2020 in creating or deleting avolume or a LUN will now be described with reference to the flowchart ofFIG. 50.

When the disk array 4000 to be worked on is selected at step 50000, itis determined whether or not the selected disk array 4000 has the iSNSclient function (step 50005). If the determination indicates that theflag is “TRUE”, namely if the disk array has the iSNS client function,processing described with respect to Embodiment 1 (steps 16005 through16030 in FIG. 16) will be performed (step 50010).

Or if the flag is “FALSE”, namely if the disk array has no iSNS clientfunction, processing described with respect to Embodiment 2 will beperformed (step 50015). To describe the specific contents of processing,where a volume is to be created, steps 30005 through 30050 in FIG. 30,where a volume is to be deleted, steps 31005 through 31040 in FIG. 31,where a LUN is to be created, steps 32005 through 32040 in FIG. 32, orwhere a LUN where a volume is to be deleted, steps 33005 through 33040in FIG. 33 will be processed.

(4) Reregistration

In this embodiment, the reregistration processing described with respectto Embodiment 2 is applied to the disk array having no iSNS clientfunction. For this reason, step 34000 shown in FIG. 34 is replaced bystep 51000 shown in FIG. 51, and only a device whose iSNS client flag isFALSE is selected from the storage device table.

This Embodiment 4, in an environment in which a disk array having theiSNS client function and a disk array having no such function arepresent in mixture, enables changes in the configuration of any storagedevice resulting from the creation or deletion of any volume or thecreation or deletion of any LUN to be reflected in registration in theiSNS database.

Since the various embodiments so far described, as their storage deviceconfigurations are altered, enable information on those configurationalchanges to be reflected in information service devices including theiSNS server and the SLP, it is made possible to promptly provide thatinformation to the network. Furthermore, since information registered ininformation service devices including the database of the SNS server orthe SLP according to configuration changes in storage devices isupdated, it is made possible to discover a volume from the hostcomputer.

1. A management method for a storage system, the storage systemcomprising an Internet Storage Name Service (iSNS) server which storesstorage node information and portal information, a management server,and a disk array which stores port information and volume information,registers the disk array's own network address on the iSNS server anddiscovers another disk array's network address from the iSNS server, themethod comprising the steps of: when adding a new disk array to thestorage system, acquiring, by the management server, the portinformation and the volume information from the disk array;transferring, by the management server, the port information to the iSNSserver; registering, by the iSNS server, the port information on theportal information; transferring, by the management server, the volumeinformation to the iSNS server; and registering, by the iSNS server, thevolume information on the storage node information.
 2. The managementmethod according to claim 2, further comprising: storing, by themanagement server, an address of the iSNS server; transferring, by themanagement server, the address of the iSNS server to the disk array;storing, by the disk array, the address of the iSNS server; andcommunicating, by the disk array, with the iSNS server by using theaddress of the iSNS server.
 3. The management method according to claim2, wherein the port information includes an Internet Protocol (IP)address of the disk array, and wherein the volume information includesan identifier of a volume in the disk array and an Internet SmallComputer System Interface (iSCSI) name corresponding to the identifierof the volume.
 4. The management method according to claim 3, whereinthe storage node information includes the iSCSI name and the identifierof the volume, and wherein the portal information includes the IPaddress.
 5. The management method according to claim 4, furthercomprising: if the disk array creates a new volume, transferring, by themanagement server, a command to create a new volume to the disk array;creating, by the disk array, the new volume; updating, by the diskarray, the volume information; transferring, by the disk array, thecommand; and registering, by the iSNS server, the command on the volumeinformation.
 6. The management method according to claim 4, furthercomprising: if the disk array deletes a volume, transferring, by themanagement server, a command to delete the volume to the disk array;deleting, by the disk array, the volume; updating, by to disk array, thevolume information; transferring, by the disk array, the command; andregistering, by the iSNS server, the command on the volume information.7. A storage system comprising: an Internet Storage Name Service (iSNS)server storing storage node information and portal information; amanagement server; and a disk array storing port information and volumeinformation, registering the disk array's own network address on theiSNS server and discovering another disk array's network address fromthe iSNS server, wherein when adding a new disk array to the storagesystem, the management server acquires the port information and thevolume information and transfers the port information and the volumeinformation, and wherein the iSNS server registers the port informationand the volume information on the portal information and the storagenode information.
 8. The storage system according to claim 7, whereinthe management server stores an address of the iSNS server and transfersthe address of the iSNS server to the disk array, and wherein the diskarray stores the address of the iSNS server and communicates with theiSNS server by using the address of the iSNS server.
 9. The storagesystem according to claim 8, wherein the port information includes anInternet Protocol (IP) address of the disk array, and wherein the volumeinformation includes an identifier of a volume in the disk array and anInternet Small Computer System Interface (iSCSI) name corresponding tothe identifier of the volume.
 10. The storage system according to claim9, wherein the storage node information includes the iSCSI name and theidentifier of the volume, and wherein the portal information includesthe IP address.
 11. The storage system according to claim 10, wherein ifthe disk array creates a new volume, the management server transfers acommand to create a new volume to the disk array, wherein the disk arraycreates the new volume, updates the volume information and transfers thecommand, and wherein the iSNS server registers the command on the volumeinformation.
 12. The storage system according to claim 10, wherein ifthe disk array deletes a volume, the management server transfers acommand intending the deleting volume to the disk array, wherein thedisk array deletes the volume, updates the volume information andtransfers the command, and wherein the iSNS server registers the commandon the volume information.